Method of charging containers for reducing ore to produce sponge metal



June 1957 s E SIEURIN ETAL 2,797,157

METHOD OF CHAR GREG CONTAINERS FOR REDUCING ORE Original Filed Feb. 20, 1948 TO PRODUCE SPONGE METAL 2 Sheets-Sheet l June 25, 1957 s. E. SIEURIN ETAL Y METHOD OF CHARGING CONTAINERS FOR REDUCING 0 Original Filed Feb. 20, 1948 TO PRODUCE SPONGE METAL 2 Sheets-Sheet 2 ':""*j:. '5 ET 2,797,157 Patented June 25, 1957 ice METHOD OF CHARGING CONTAINERS FOR RE- DUCING ORE T PRODUCE SPONGE METAL Sven Emil'Sieurin, Gamlegard, Forslovsholm, and Edvin Verner Olsson, Hoganas, Sweden, assignors to Hoeganaes Sponge Iron Corporation, Dover, Del a corporation of'Delaware Section 1, Public Law 690, August 8, 1946 Patent expires May 11, 1966 3 Claims. (CI. 75-33 7 This application is a division of our copending application Serial No. 9,848, filed February 20, 1948, now ,U. S. Patent No. 2,730,283, issued January 10, 1956.

This invention relates broadly to the reduction of ores .and oxides of metals and more particularly to the reduction of these raw materials to produce sponge metals. The invention relates especially to a method of the type under consideration according to which the ores and oxides of the metals and reducing agent are arranged in layers inceramic containers which after the charging operation are heated to the reducing temperature, for instance according to the Hogan'als process.

According to this process and other methods of the same kind it has hitherto been customary to charge the containor with the different materials in substantially horizontal layers. The sponge metal produced, however, has not been of so uniform quality as desired.

As in some cases for special purposes it is of great importance to have access to an even and highly reduced sponge metal there have been several investigations with the aim to improve the methods for producing sponge metal. It has thereby been discovered that the above mentioned drawback can be reduced or eliminated if the layers of metal EOICS or oxides are made with equal thickness all over the layer. For obtaining such layers it has been proposed to mix the ore or metal oxide with a binder and mold it to briquettes of different form. It has also been suggested to mix the reducing agent with (a binder and mold it in the form of a container which surrounds a cavity with straight walls and thereafter charge the container with metal ore or oxide, which thereby forms .a layer with equal thickness. The addition of a binder and the forming of the metal ore or oxide and the reducing agent, however, are connected with considerable costs for the binding agent and the forming and mixing operations which are hardly compensated by the advantages to be gained by using such methods.

The main purpose of the present invention is to create a more simple and less expensive method of charging the ceramic containers used in the process known by those skilled in the art under the name of the HtSganiis process so that the sponge metal produced will be of quite satisfying and uniform quality. According to the Hoganas process the reduction is carried out in cylindrical ceramic containers which stacked upon one another in a kiln or a furnace are heated to reduction temperature. Previous to the stacking the containers are charged with metal ores or oxides in horizontal layers embedded the reducing agent. The metal one or oxide is hereby in free flowing pulverous form, such as ore concentrate, and the reducing agent is also in pulverous form preferably somewhat coarser than the metal oxide or ore. When charging the metal ore it is, however, diflicult to obtain layers with substantially equal thickness as underlying layers are disturbed when charging an overlying layer and when the charge is packed or stamped to prevent further disturbance at the handling and stacking of the container in the furnace.

In contra-diction to the above described normal charging the containers according to this invention are charged in such a way that the layers of metal ore or oxide will be substantially vertical and embedded in the reducing agent still in their free flowing form without any addition of binding agent. Preferably the layers are given a form with plane or convex surfaces to facilitate the removal of ash and reducing agent attached to the pieces of sponge metal obtained when the reduction is completed.

The charging of the containers is preferably carried out in such a way that sockets of sheet-metal in a shape corresponding to the form of the ore layers are introduced vertically into the container with their lower ends spaced from the bottom of the container whereupon reducing agent is fed into the container outside the sockets, the container preferably being vibrated to cause the reducing agent to cover the bottom of the container even below the lower ends of the sockets. Then the metal ore or oxide is introduced into the sockets and these are removed from the container either concurrently with the rising of the ore level within them or after they arethe ash and the unburned reducing agent in the common way, the lumps of sponge metal then being further cleaned in a rotating cleaning drum. Because of the straight or convex surfaces of the sponge metal lumps these are readily released from adhering impurities including ash and reducing agent.

According to the invention it is thus possible to obtain layers of the material to be reduced with the desired form described above without introducing any binding agent with accompanying mixing and forming operations. This is due to the fact that the layers during the forming are limited by the sockets and, when formed and the sockets removed, are limited by the surrounding reducing agent. This limiting action can be supported by vibrating the container and its content during the charging and before removing the sockets. Hereby the content is packed and attains a higher density so that the layers of metal one or oxide are better supported by the surrounding reducing agent and at the same time they have also packed themselves so that their need for support in order to'maintain the desired form is minimized.

However, the invention also contemplates an apparatus for carrying out the above described method for charging the reduction containers. This apparatus is highly efiective in reducing the hand-work and the time required for charging the containers so that the charging costs are considerably reduced in relation to the same costs when charging the containers with horizontal layers according to the older methods. Thus, when using the method and apparatus according to the invention it is possible to obtain quite as good results as with the previous methods involving the use of a binding agent and forming the charge as briquettes. or the like and this at a decreased cost which is substantially the same as when using horizontal layers of free flowing components or even still lower.

position.

fvertical section on anenlalrged scale of a part of the apparatus on the line IIII of Fig. l, and Fig. 3 is a horizontal section of the reduction container with the sockets f the charging apparatus on the line III III of Fig. 2.

Referring to the drawings the apparatus is built up of j a structure 2 of iron beams which supports a storage bin 4 for metal oxide or ore and a storage bin 6 for reducing agent. -vided with a sector door 8 and 9 respectively with regula- Each bin 4 and 6 are at their lower ends protion means 10 and 11 for the controlling of the flow of material fnom the bins. Beneath each bin 4 and 6 there is provided a conveying belt 12 and 13 respectively. The

material flows onto the belts from the sector doors 3, 9.

The flow of material is restricted sideways by means of guiding plates 14. The thickness of the layer of material on the belt is equalized by means of an adjustable scraper 16, which is operated with the lever 18 over the rod 20 from the hand wheel 22. The belts are as usual provided with bearing and end rollers and are driven by 'means of a chain.

tainer 30. The inner hopper 24 is by means of partition walls 32 divided in three compartments 34. At the upper end the partition walls are combined two and two to form an edge atwhich there is provided a hinge 36 and a swingable plate 38 with a projecting Mg 40 by means of which the plate 38 may be connected to adjusting and fastening means, not shown, for adjusting the width of the inlet openings to the compartments 34. Each compartment 34 terminates in a socket42 with parallel Walls.

These sockets project below the flange 28 of the outer hopper to such an extent that when the flange abuts the opening of the conain'er 30 the lower ends of the sockets will be spaced from the bottom of the container. For the purpose of strengthening the sockets against lateral movements they are provided with flanges 44 and interconnections 46. s V

The container 30 rests on a supporting ring 48 under which is arranged a casing 50 for an electric vibrator or the like. The casing 50 is supported by hydraulic jack 52 with a stem 54, a plunger 56 and an inlet and outlet tube 58 for the working medium. This jack '2 is arranged in a structure comprising a funnel 60 for collecting waste and a grate 62 through which superfluous material may fall down into the funnel 60.

The operation of the apparatus is as follows:

Before the beginning of the operation the bins 4 and 6 are charged with the materials for the reducing container 30, viz., the bin 4 with metal ore or oxide in free flowing granular form and the bin 6 with reducing agent also in free flowing form. The sector doors 8, 9'are I operated to allow the materials to flow out of thebins at a predetermined rate. An empty container 30 to be charged is conveyed to the apparatus by means of a conveyer, for instance a rolling bed, and placed on the supporting ring 48 which at this time is in its lowered The' container is then moved upwardly by means of the hydraulic jack 52 so that the sockets 42 are introduced in the same and unto the rim of its opening abuts the flange 28 whichunderneath is provided with into the space in the container outside the sockets 42.

The container is hereby vibrated with a vibrator, not shown, in the casing 50 so that the reducing agent is brought to cover the bottom of the container also beneath the ends of the sockets. As soon as the bottom is covered the metal ore or oxide can be charged by starting the conveying belt 12 below the bin 4. The flow of material to be reduced is divided in three parts by the partition walls 32. When the plates 38 are correctly adjusted these walls are arranged to divide the flow of material so that when the conveying belt is stopped the material fills the sockets in the container to the same level somewhat below the rim of the container 30. The charging of the reducing agent is continued during the charging of the ore and preferably also the vibrating of the container. When the container is filled it is lowered by means of the hydraulic jack until it is free of the projecting lower ends of the flanges 44 and moved away, whereby at the same time reducing'agent is brought to cover the upper ends of the vertical layers formed.

The diiferent steps in the charging operation, namely elevating the container 30, starting the conveying belt '13 for reducing agent, starting the vibrator, starting the enter only has to start the process, whereupon the different steps are timed without-any manual operation.

What is claimed is:

l. The method of charging containers for reduction or metal oxides without melting which comprises the steps of introducing a pulverous reducing agent in free flowing form into the container to form a lining for the side walls and bottom thereof while maintaining one or more vertically extending cores spaced from the side walls and the bottom of the container for the reception of a material subsequently to be reduced within the container, and introducing into the container a pulverous metallic oxide in free flowing form to fill said one or more cores.

v2. The method as defined in claim 1 in which the container is vibrated'during the period of introduction of the aforementioned materials, in order to pack same.

3. The methodasdefined in claim 2 in which said core or cores are provided by the introduction of one or more hollow sockets relatively movable with respect to the container and spaced from the side walls and bottom thereof, said sockets being inserted in the container prior to the introduction of any of the materials thereinto, andbeing withdrawnfrom the container subsequent to the introduction of both of the materials into the container.

References Cited in the file of this patent UNITED STATES PATENTS 149,241 Peckham Mar. 31, 1874 .1,605,096 Campbell Nov. 2, 1926 2,344,901 Routh Mar. 21, 1944 2,386,072 Stewart Oct. 2, 1945 

1.THE METHOD OF CHARGING CONTAINERS FOR REDUCTION OF METAL OXIDES WITHOUT MELTING WHICH COMPRISES THE STEPS OF INTRODUCING A PULVEROUS REDUCING AGENT IN FREE FLOWING AND BOTTOM THEREOF WHILE MAINTAINING ONE OR MORE VERTICALLY EXTENDING CORES SPACED FROM THE SIDE WALLS AND THE BOTTOM OF THE CONTAINER FOR THE RECEPTION OF A MATERIAL SUBSEQUENTLY TO BE REDUCED WITHIN THE CONTAINER, AND INTRODUCING INTO THE CONTAINER A PULVEROUS METALLIC OXIDE IN FREE FLOWING FROM TO FILL SAID ONE OR MORE CORES. 